17 cases of acute myocardial infarction with no or insignificant narrowing of major coronary arteries on angiogram and without any-other types of heart disease were found in a series of 133 consecutively studied patients with acute myocardial infarction(12,7%). There were no differences in risk factors between groups. Although the infarction site were similar in both groups, the patients with normal coronary arteries had fewer complications during hospitalization(p<0.05) and lesser ST segment change during the exercise test before discharge(p<0.05). In the hemodynamic fingings, cardiac index, left ventricualr and diastolic pressure and resional wall motion were similar in both groups of the patients, but ejection fraction was higher(p<0.05) in the patients with the normal coronary arteries.